The static inundation map of the Moolap / Point Henry area is shown in Figure 6-36. This figure shows that under a 1% AEP event with 0.0 m SLR only the saltpans and habitat areas on the eastern fringe of Point Henry are inundated. In a 1% AEP event with 0.5 m SLR Point Henry Road is likely to be cut, the flooding in this instance is likely to be from the western side of the point, with minimal flood inundation from the eastern side. Under a 1% AEP event with 0.8 m SLR the inundation from east becomes more significant.

The Newcomb / Moolap area was modelled dynamically, as shown in Figure 6-37. The events under which inundation occurs at key locations, identified by the red dots in Figure 6-37, have been listed in Table 6-18. Inundation is largely via the large drainage channel around the western and southern edge of the salt pans. The Geelong-Portarlington Road is overwashed at the western end in a 1% AEP event with more than 0.8 m SLR. South of the Geelong-Portarlington Road, inundation is only apparent in a 1% AEP event at more than 0.8 m SLR. Above 0.8 m SLR (1.1 m and 1.4 m scenarios) water flows over the road and inundates significant areas in a 1% AEP event. West of the salt-works, the CSIRO building is located above any predicted inundation. The timing of inundation is presented in Figure 6-38.

Table 6-18     Critical inundation locations identified in the Newcomb / Moolap model

The results of the overtopping assessment for the Geelong sea-walls are presented in Table 6-19. Discharges are presented in units of litres per second per metre (L/s/m). The results show that under the higher sea-level rise scenarios, the overtopping hazard of the structures increases. It should be noted that the wave energy in this location is generally low, although the volumes calculated are high due to increased wave heights during storm conditions; this is more related to the storm-tide level and lack of freeboard i.e. the vertical difference between the structure crest elevation and the storm-tide water elevation. Hence, the failure volumes are noted as ‘overwashed’ rather than fail, as it is unlikely the structures would fail. The calculations assume the condition and the elevation of the current structures are maintained. The calculations also assume the depth of water at the toe does not decrease over time due to sedimentation, thus, for the sea-level rise scenarios are conservative. Figure 6-39 shows the possible maximum flood extent in an overtopping event. This is a conservative indication of the extents, as a static model has been utilised, rather than a volumetric placement of the overtopping discharge volumes behind the structures based on the topography.

Table 6-19     Overtopping discharge volumes